A technique has been proposed in which a gateway of an on-vehicle communication device or the like receives, from a management server, update programs for control programs of ECUs (Electronic Control Units) as on-vehicle control devices, and each ECU rewrites the control program from an old version to a new version by using the received update program, thereby remotely executing program update for the ECUs in the vehicle through wireless communication (refer to Patent Literatures 1 and 2).